Control method and apparatus



April 11, 1939. J. RJGREEN ET AL 2,153,922

CONTROL METHOD AND APPARATUS Filed Feb. 4, 1935 7 Sheets-Sheet l 2 FOREHEARTH a PLUNGER Q ORIFIGE 14 VENTOR. JOHN R. GREEN ANKER E.KROSH COLEMAN E MOO E BY ROY ULLMAN W4 XW A TTORN E Y April 9- J. R. GREEN ET A1. 2,153,922

CONTROL METHOD AND APPARATUS Filed Feb. 4, 1955 7 Sheets-Sheet 2 HIHHHHHH HIHHHHHH TH WARE FORMING UF BY ROY ULLMAR F I 28 ATd NEY I Ap 1 1939- J. R. G REEN ET AL 2,153,922

7 CONTROL METHOD AND APPARATUS Filed Feb. 4, 1935 7 Sheets-Sheet 3 I "II I AI T NEY' J. R. GREEN ET AL 53,922

CONTROL METHOD 'AND APPARATUS Filed Feb. 4, 1935 7 Sheets- Sheet 4 April 11, 1939.

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April 1939- J. R. GREEN ET AL 2,153,92

CONTROL METHOD AND APPARATUS Filed Feb. 4, 1955 '7 Sheets-Sheet 5 INVEN JOHN R.

ANKER E COLEMAN B. 00 E ROY U M April 11, 1939. J. R. GREEN ET AL CONTROL METHOD AND APPARATUS Filed Feb. 4, 1935 '7 Sheets-Sheet 6 FIG 7 A TTORNEY April 11, 1939. J. R. GREEN ET AL CONTROL METHOD AND APPARATUS Fild Feb. 4, 1955 '7 Sheets-Sheet 7 N R.GR EN -ask: OY ULLMAN INVENTOR. COLg B.

Z, A TTORNEY Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE CONTROL METHOD AND APPARATUS John R. Green, Philadelphia, Anker E. Krogh, Erdenheim, Coleman B. Moore, Carroll Park, and Roy Ullman, Roslyn, Pa., assigncrs to The Brown Instrument Company, Philadelphia, Pa., a corporation of Pennsylvania Application February 4, 1935, Serial No. 4,738

Claims. (Cl. 49-55) In the manufacture of bottles and other glass articles by means of modern automatic glass ware machinery, the character and value of the product is directly dependent, as a general proposi- 5 tion, upon the production and delivery to the machinery of glass gobs, or masses of the proper weight and viscosity. In a glass feeder of ap-,

proved type for use with which the present invention is well adapted, the glass gobs are segrelO gated and delivered from a glass feeder comprising a receptacle into which molten glass is delivered and to which heat is supplied byregulable heating means to maintain and regulate the temperature of the molten glass therein ,and from which the glass is discharged in a stream from which the gobs are segregated by a periodically operating clipper or shearing device which forms a gob by cutting off a section of the glass stream discharged.

In the most usual form of such a glass feeder, the glass forming the stream from which the gobs are severed is intermittently expelled or extruded througha discharge orifice in the bottom wall of the receptacle by a reciprocating plunger moving axially of the orifice. With glass of a given composition and temperature and with the glass extruding plunger making strokes of uniform length at a constant frequency, and with a corresponding frequency of operation of the glass stream severing means, the glass gobs separated should and will be of uniform weight and viscosity with glass of a given composition and temperature. In practice, however, it has been found impossible to maintain a constant glass discharge temperature and only a relatively-small. variation in glass temperature is required to produce a change in glass viscosity sufficient to materially effect the weight of the gobs of glass severed, since the rate of discharge depends not only on the measuring action of the extruding plunger, but on the gravitational flow of the glass, and that flow is a function of the glass viscosity.

Slight changes in glass gob weight are prohibitive in many cases. For example, in the manufacture of bottles for expensive perfumery, a very slight change in the glass gob weight will result in a variation in bottle capacity which will not be tolerated by the perfumery bottler or distributor.

cerned, compensation for changes in glass viscosity through a considerable range can be efiected by varying the stroke of the extruding plunger, provided that the necessity for the adjustment and the extent of adjustment required is made apparent with suitable promptness and accuracy.

Insofar as the glass gob weight is con- In general also the operation of the glass ware machinery can be adjusted to compensate for a considerable variation in glass viscosity, if the need for such adjustment is made apparent with suitable promptness and accuracy. 5 It would seem to becomparatively simple to provide for automatic glass temperature measurements, and a control of the glass feeder heating provisions in automatic response to said measurements, effective to maintain an approximate- 10 ly constant glass discharge temperature, and to keep the maximum glass temperature and viscosity variations from predetermined normals suitably small. In practice, however, temperature control apparatus of the type just mentioned de- 15 vised for and successfully employed in effecting control operations in other arts, 'has been found unsatisfactory in the control of glass feeders, primarily, it is believed, because they necessarily involve and permit relatively rapid though small 20 fluctuations in the temperature and viscosity of the glass discharged, which cannot be suitably compensated for, either through the regulation of the plunger stroke to maintain an approximately constant glass gob weight, or by the ad- 25 justment of the article forming machinery to compensate for variations in glass viscosity.

In controlling the operation of a glass feeder of the general type mentioned above, we have found that better results are obtainable with a 30 control which, while it may permit of an appreciable variation in that temperature, insures a slower and more gradual rate of temperature change in either direction, than is obtainable with the smaller range of temperature variations 35 but more rapid fluctuations in glass temperature, characteristic of control effected by temperature measuring and control provisions of the character heretofore developed and found satisfactory for controlling the operation of oil heating and 40 other industrial furnaces. Our invention, therefore, has for a general object, the provision of a control method and apparatus which, while they may permit an appreciable variation .in glass temperature, will keep those variations within a 5 range not great enough to be seriously objectionable, and will avoid an objectionably rapid fluctuation in the discharge temperature at any time. A more specific object of the invention is to provide apparatus constantly furnishing an 50 accurate measure and record of the essential glass temperature conditions forming a guide for the manual adjustments of the feeder heating supply and the operation of the plunger, and providing an automatic control of the heat supplied 55 to the feeder adjacent the feeder discharge orifice, effective to hold the discharge temperature within suitable limits, without causing undesirably abrupt variations therein.

In a preferred mode of carrying out the present invention, we make use of a single measuring and control instrument and associated means for measuring the temperature of the glass in the feeder adjacent the discharge orifice and the temperature of the glass in a portion of the feeder relatively remote from the discharge orifice, at alternate intervals, with provisions controlled thereby for increasing and decreasing the supply of heat to the portion of the glass in the feeder adjacent the discharge orifice at a rate sufliciently rapid to slow down and equalize changes in glass discharge temperature which result from such causes as an improper adjustment of the means employed to supply heat to the main body of glass in the feeder, and changes'in the temperature at which the molten glass is supplied to the feeder.

With timely and accurate knowledge-of the values of and changes in the two above mentioned glass temperatures, it is possible to adjust V delivery of gobs suitably uniform in weight, notwithstanding changes in glass viscosity, and to effect the glass ware machinery adjustment required to compensate for the changes in glass feeding conditions.

The temperature measuring and control instrument employed may obviously take various forms, and in particular may be similar in general construction and mode of operation to measuring and control instruments of various types now in use for other purposes. In practice, we have obtained excellent results with, and prefer to make use of a self'balancing potentiometer measuring and control instrument of the character disclosed in the Harrison patent, 1,946,280, granted February 6, 1934, and our invention comprises modifications in and additions to the instrument disclosed in said patent giving the instrument operating characteristics especially desirable for glass feeder measurement and control purposes, but useful for other purposes also. An especially desirable characteristic of our improved instrument is its capacity for making each control action dependent upon an accurate measure of one or two alternately measured temperatures. This is peculiarly important in the case of a self balancing potentiometer employed to alternately measure temperatures which differ from one another as do the temperatures of the glass in the feeder at points relatively adjacent to and remote from the feeder outlet orifice. In the alternate measurement of such dissimilar temperatures by a self balancing potentiometer, the number of balancing operations following a measurement of one temperature, required to obtain an accurate measurement of the other temperature, will vary, but should be kept as small as possible, since an increase in the number of balancing operations prov longs the periods between successive control operations, which is undesirable.

The general features of the present invention are as applicable to a glass feeder of the type in which the fluid pressure to which the glass at the inlet of the discharge orifice is periodically varied to effect a periodical discharge through the orifice, as to the type of glass feeder, hereinbefore mentioned, in which a reciprocating extrusion plunger is employed.

Our invention contemplates a direct measure of the gob weight either before or after the conversion of the gob into a bottle or other article made in the glassware machine and the use of the weight measurement as a guide for manual, or automatic control of the adjustment of the feeder plunger.

The various features of novelty which characterize our invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects obtained with its use, reference should be had to the accompanying drawings and descriptive matter in which we have illustrated and described preferred forms of apparatus for use in the practice of the present invention.

Of the drawings:

Fig. 1 is a diagram illustrating a glass feeder mechanism and certain control and temperature measuring features associated therewith;

Fig. 2 is a diagrammatic representation of control circuit provisions adapted for use in the automatic adjustment of a thermally actuated control valve shown in Fig. 1;

Fig. 2A is a diagram illustrating a modification of the control circuit shown in Fig. 2 adapted for use in adjusting a'motor actuated control valve which may replace the thermally actuated control valve shown in Fig. 1;

Fig. 2B is a diagrammatic representation of means employed to adjust the glass feeder in automatic response to changes in glass gob weight.

Fig. 3 is a perspective view of parts of a potentiometer measuring and control instrument diagrammatically shown in Fig. 1;

Fig. 3A is a perspective view of the control table and immediately related parts of the instrument shown in Fig. 3;

Fig. 4 is an elevation of the end of the instrument partiallyshown in Fig. 3, which is at the I right in Fig. 3;

Fig. 4A is an elevation, taken similarly to Fig. 4, showing parts of the instrument obscured in Fig. 4 by parts removed in Fig. 4A;

Fig. 5 is an elevation of the control instrument as seen from the left of Fig. 3, with parts broken away and in section;

Fig. 6 is a rear elevation of a portion of the instrument shown in Fig. 3;

Fig. 7 is a section on the line 1-1 of Fig. 6;

Fig. 7A is a partial section on the line IA-4A of F18. 6;

Fig. 8 is an elevation illustrating a detail of the instrument shown in Fig. 3;

Fig. 8A is an elevation illustrating a modification of Fig. 8;

Fig. 9 is an elevation of the apparatus shown in Fig. 8 with parts broken away and in section, as seen from the right of that figure;

Fig. 10 is an elevation of a portion of the appa. ratus shown in ,Fig. 8 as seen from the right of that figure; and

Fig. 11 is a view showing a portion of a record sheet shown in Fig. 3 with the record lines formed thereon by the instrument.

In Fig. 1, we illustrate the use of our invention in connection with a glass feeder of known type adapted to deliver gobs of glass for use in bottle forming machinery not shown. The feeder comprises a glass receptacle structure, which is commonly referred to as a forehearth, and com prises two portions, one commonly called the channel and the other the spout. Molten glass is supplied to the channel portion of the feeder receptacle from a tank, not shown, and flows from the channel into the spout, The latter is provided with a submerged discharge orifice in its bottom wall in line with a vertically reciprocating plunger'U which moves upward to open the orifice, and on each down stroke extrudes through ,the orifice a quantity of glass equivalent in amount to an individual gob, and at the conclu-v sion of its down stroke, substantially closes the orifice. Clipper shears beneath the orifice and operating in timed relation with the plunger movements, periodically cut oil the lower portion of the stream or attenuating body of glass depending from the orifice, to thereby form a glass gob for conveyance by suitable mechanism (not shown) to the bottle forming machinery.

The glass extruding plunger U, as shown, has astem pivotally connected at U' to a plunger operating lever U which is oscillated about its pivot W by an eccentric U The latter is continuously rotated about a stationary axis by an electromotor U one of the energizing conductors, U and U", of which includes a resistance U which may be varied'to vary the speed of the motor. The vertical movements given the lever U by the cam U have a fixed upper limit, but

their lower limits are adjustable and are determined by the engagement of the lever with a stop W carried by a vertical screw U threaded through a fixed support U The elevation of the stop U and thereby the length of the stroke of the extruding plunger, may be adjusted by a rotation of the screw U which may be efiected automatically when desirable, but, as shown, is effected manually. With glass of a given viscosity, the amount of glass .expelled on each plunger downstroke, and the size of the gob severed by the clipper, will depend on the length of the stroke of the plunger.

While the glass delivered to the forehearth from the tank is always molten, it is not practically feasible to maintain a feeder discharge which is high enough and constant enough by regulating the tank glass temperature, and the feeder is supplied with glass heating means. In the arrangement shown in Fig. 1, the heat supply means comprises manually adjustable fuel burners U for supplying heat to the glass in the channel portion of the forehearth, and an automatically adjusted burner U for supplying heat to the glass in the portion of the spout adjacent the discharge orifice.

In the preferred mode of use of the apparatus shown in Fig. 1, the burners U are adjusted as required to supply a considerable portion of the feeder heat requirement but are not relied upon to maintain a constant channel glass temperature or to prevent that temperature from being substantially lower, ordinarily 100 or so lower than the desired glass temperature, and the burner U is adjusted as required to raise the temperature of the glass adjacent the discharge orifice and, prevent that temperature from departing more 7 than a few degrees from a predetermined normal temperature and at the same time preventing change in that temperature, except at a rate so slow that ample time will be provided to determine the need for, and to effect the adjustments of the stop U necessary to keep the individual glass. gobs delivered practically uniform in weight and the adjustments of the bottle machinery necessary to compensate therein for the efiect of changes in glass viscosity resulting from the changesin glass gob temperature. The desired glass temperature regulation requires suitableglass temperature measurements and, preferably, records of the measurements. In the apparatus shown, the temperature of the glass in the spout adjacent the orifice is measured by means including a thermocouple l extending through the spout wall with its tip in contact with the glass. Thetip may be covered by a protecting tube or may be bare so as to be more quickly responsive to changes in temperature of the molten glass. A thermocouple l5", which may be similar to the thermocouple l 5, extends into contact with the glass in the channel. With the apparatus disclosed, the temperatures to which the two thermocouples are exposed are separately measured and are suitably recorded. In effecting adjustments of the extruding plunger strokes, and of the bottle making machinery, account should be taken not only of the spout temperature but of the subsequent eflect on that temperature of the channel glass temperature. With the form of apparatus disclosed, the temperature measurements made by the use of the thermocouple 15 may be taken into account in adjusting the burners U but the burner U is adjusted automatically in response to the measurements of the temperature to which the thermocouple l5 responds. I

In the diagrammatic showing of Fig. 1, T represents the casing of a measuring, recording and control instrument mounted on a panel T and to which the terminals of the thermocouples l5 and I5" are connected, and which includes the circuit parts shown in Fig. 1. The instrument enclosedby the casing T, includes a switch 39 shown in detail in Figs. 8-10, which operatively connects the thermocouples l5 and I5" alternately to the instrument and during a portion of the time in which the thermocouple I5 is operatively connected to the instrument, the latter subjects the thermally actuated valve V, regulating the supply of fuel to the burner U", to control effects dependent upon the then existing temperature of the thermocouple 15.

The instrument enclosed by the casing T of Fig. 1, and the hereinafter described mechanical features, of which are shown by Figs. 3 to 8, is a self-balancing potentiometer instrument including a potentiometer measuring circuit which as shown diagrammatically in Fig. 1, is of conventional split potentiometer type. The potentiometer circuit of Fig. 1 includes a battery or other source of energizing current S in series with a calibrating resistance S in a circuit branch to the ends of which are connected three other circuit branches. One of the latter includes .a slidewire resistance 21 and a ballast resistance S 'The second of said three branch circuits includes a calibrating resistance which determines the measuring range of the potentiometer circuit, and the third includes ballast resistances S" and S The circuit branches including the slide-wire resistance 2| and the resistance S are each connected at one end to one end of the branch including the battery S through a ballast resistance S A galvanometer 2 has one terminal connected to the circuit branch including the resistances S" and S intermediate of the latter, and has its other terminal connected to a switch part S which in the measuring condition of the apparatus engages a contact S connected by a conductor to the potentiometer circuit terminal S of the switch 39. The cooperating potentiometer circuit terminal S is connected by a conductor S to one end of a slide wire resistance S alongside the slidewire resistance 2| and connected to the latter by a bridging contact 20. The latter is movable along the slidewire resistances to vary the point along the length of the resistance 2| at which the terminal S is connected to the latter, and to correspondingly vary the amount of the resistance S" in circuit for the known purpose of preserving an approximately constant resistance in the galvanometer circuit.

If with the switch 39 adjusted to connect the terminals S and S to the terminals of one or the other of the thermocouples i5 and I5", the voltage of the thermocouple so connected to the potentiometer circuit is equal and opposite to the potential difference between the portion of the slide-wire resistance 2| then engaged by the contact 20 and the terminal of the galvanometer connected to the circuit branch including resist ances S" and S, the potentiometer will be in balance, but not otherwise. the resultant deflection of the galvanometer pointer 2 will set into operation the instrument rebalancing mechanism to thereby automatically adjust the contact 20 along the slide-wire resistance 2! until the potential difference between the points of the potentiometer circuit to which the thermocouple is connected is equal and opposite to the thermocouple, and the potentiometer is thereby balanced.

As those skilled in the art will understand, the resistance 8' may be of such value and have such a temperature coefiicient as to compensate for variations in the thermocouple cold junction temperature. Fig. 1 conventionally illustrates calibrating provisions including a resistance S", a standard cell 8 a shunt resistance S and switch contacts S and S into engagement with which the switch part S may be moved to determine the changes in the amount of the resistance S in circuit required to compensate for changes in voltage of the energizing ource S. As the need for and mode of eifectin such recalibration of the energizing circuit from time to time are well known, they need not be'further referred to herein.

In respect to most of its potentiometer recording features, the instrument shown herein is similar in form, as well as in substance, to the instrument disclosed in the joint application of Harrison, Grauel and Kessl'er, Serial No. 546,290, filed June 23, 1931, and in respect to a number of its control features, the instrument shown herein is similar to the instrument disclosed in the above mentioned Harrison patent. The manper in which we make use of the features of said application and patent, and combine them with other control featuresTfor the purposes of the present invention, is set forth in the following description of the construction and operation of the instrument disclosed herein.

The mechanical relay mechanism of the instrument shown which'includes a driving shaft i2, constantly rotated by a driving motor, not shown, is controlled by the deflection of the galvanometer pointer 2' away from its normal zero position. They serve not'only to periodically adjust the contact 20 as required to rebalance the potentiometer circuit, but also to move a pen or other recorder carriage 23 along a travelling record strip 25 to record the varying value of the quantity measured on said strip. The means for effecting control functions include a control table A, and means by which a control member, which in the form shown in Fig; 1, is a valve V control- When not in balance,

ling the supply of fuel to the burner U", is periodically adjusted by the relay mechanism, if and when the recorder carriage 23 is then displaced in one direction or the other from the control table A. The latter is normally stationary but may be manually adjusted along the path of movement of the carriage 23 as by the rotation of the knob B shown in Fig. 1 and any suitable connection between said knob and table. The position of the control table A corresponds to, and determines the normal value, and the position of the carriage 23 corresponds to, and measures the current value of the quantity measured.

The mechanism through which the deflection of the galvanometer pointer 2' controls the adjustments of the recorder carriage 23 and the rebalancing of the potentiometer circuit on a variation in the quantity or value measured by the galvanometer, comprises a pointer engaging and position gauge element 3. The latter is pivotally supported and in connection with the herein'after mentioned shaft 6 has a loading tendency, which may well be due partly to spring and partly to gravitational action, to turn upward into the position in which one or another of the shoulders 5 of the member 3 engage the pointer 2. The element is engaged by, and turns, with the arm 6' of a rock shaft 6, A spring i0 tends to hold a rocker 8 which is journaled on a pivot 9, in the position in which the rocker engages an arm I secured to the shaft 6 and thereby holds the latter in a position in which the shoulders 5 are all below the pointer 2'.

Acam H which is carried by shaft I2 constantly rotated by the instrument driving motor through 4 a speed reduction gearing, turns the rocker 8 about its pivot against the action of the spring i0, once during each revolution. This allows the arm I to turn counter-clockwise, as seen in Fig. 3, until the corresponding angular movement of the shaft 6 is interrupted by the engagement of one or another of the shoulders 5 of the member 3 with the galvanometer pointer 2'. The shoulders 5 are so arranged that the turning movement of the shaft 6 and arm 1, thus permitted, will be greater orless according to the deflective position of the 1 pointer 2' at the time.' When the arm I thus turns counter-clockwise, a lateral projection 1' of that arm engages and turns a secondary pointer element I4 into a position corresponding to the then deflection of the pointer 2'. The secondary pointer i4 is loosely journaled on the shaft 6, and has a gravital loading tendency to turn in the clockwise direction as seen in Fig. 3, so that the arm I 4 normally bears against the projection 1' of the arm I.

At the end of each angular adjustment of the secondary pointer l4 into a position corresponding to the then deflection of the galvanometer 2, one or another of the three shoulders I5A, i513 and l5C of a locking member I5, engages the bottom wall of a slot il in the member H and thereby frictionally holds the latter in the position occupied by it when such engagement occurs. When the pointers 2 and il occupy their neutral positions, the shoulder i5B of the member i5 comes into locking engagement with the member I. When the galvanometer pointer 2 has deflected to the right, as seen in Fig. 2, as it does when the actual value of the quantity measured is lower than that indicated by the previously made and still existing potentiometer adjustment, the secondary pointer I4 is engaged and locked by the shoulder I5C. When the galvanometer pointer deflects in the opposite direction from its neutral 'by the existing potentiometer adjustment, the

pointer I4 is engaged and locked by the shoulder ISA of the member I5. The locking part I5 is given a tendency to move into locking engagement with the secondary pointer I4 by the spring l0, but is periodically held out of such engagement by the action on its projection I5D of a projection I 6A carried by a ratchet lever I6 pivoted at I6B.

A spring I6C gives the lever I6 a tendency to turn forward in the clockwise direction, as seen in Fig. 3, but throughout the major portion of each rotation of the shaft I2 the lever I6 is held in a retracted position by a cam II carried by said shaft and engaged by the cam follower roll I6D carried by the lever I6. The ratchet lever I6 is operatively connected to two pawls 86E and I6F cooperating with a toothed wheel 88. Each of said pawls has a gravital tendency to occupy a position in which it does not engage the teeth of the wheel I8, but one or the other of the pawls is brought into engagement with the teeth of the wheel on each forward or clockwise movement of the lever I6, if the locking part i5 is then at one side or the other of the intermediate or neutral position which it occupies when the galvanometer pointer 2' is in its neutral position.

The position assumed by the part i5 when in looking engagement with the secondary pointer M controls the action of the pawls 56E and I6F by virtue of the fact that a collar or hub portion I5 of the part I5 carries a spring pawl engaging arm 95E. The movement of the locking part 05 into the position in which its shoulder 85A engages the secondary pointer Hi causes the arm H513 to move the pawl IBE into operative engagement with the teeth of the ratchet wheel 88, and the clockwise or forward movement of the ratchet lever l6 then gives a clockwise adjustment to the ratchet wheel. Conversely, when the part I5 moves into the position in which its shoulder I5C engages the secondary pointer I4, the arm I5E shifts the pawl iBF into operative engagement with the wheel 88,

and the latter is then adjusted in the counter-- clockwise direction.

The extent of the adjustment then giventhe wheel I8 is made dependent upon the position of the secondary pointer I4, as said position determines which of the various shoulders I6G and I6G. of anarm l6G carried by the lever I6 shall then engage a projecting portion I4" of the secondary pointer I4 and thereby arrest the forward movement of the ratchet lever I 6. In the neutral position of the galvanometer pointer and secondary pointer I4, the projection I4" of the latter engages the central shoulder I6G" of the arm l6G and the lever I6 is then held against any operative movement in the clockwise direction. When the secondary pointer position is more or less to.

one side or the other of its neutral position, the

'portion I4" engages an upper or lower shoulder 'I6G' more or less distant from the central shoulby varies the amount of said resistance in the potentiometer circuit. The resistance adjustmentsmade in response to a deflection of the galvanometer pointer in one direction away from its neutral position rebalances, or tends to rebalance, the potentiometer circuit and thereby returns, or tends to return, the galvanometer pointer to its neutral position.

The rotation of the wheel i8 adjusts the recorder carrier 23 by virtue of the fact that the teeth of the wheel I8 are in mesh with the teeth of a gear carried by a carriage adjusting shaft 22 which is in threaded engagement with the pen carriage. The shaft 22 is formed with a thread groove 22' of coarse pitch which receives a cam or mutilated screw thread rib 23' (see Fig. 5) secured to the carriage 23, so that the latter is moved longitudinally of the shaft 22 as the latter.

uprising projections. Those projections include two apertured ears 23a at the rear corners of said body portion transverse to and through which the shaft 22 extends; two projections 23?),

one at each front corner of said body portion which bear against the inner edge and upper side of the lower flange of a channel bar or rail 24 forming part of the instrument framework, and three intermediate projections 230 which extend in vertical planes transverse to, and are arranged in a row parallel to, the shaft 22' and rail 24. In addition the body portion of the carriage frame is provided with a forwardly extending tongue passing beneath the rail 24 and terminating in an uprising pointer or index 23d adapted to cooperate with a scale marked on the front face of the rail 24 to indicate the position of the pen carriage, and the value of the quantity measured and recorded by the instrument.

The projections 230 support a small shaft 236 forming a support for a pen support 23f on which the pen 25 ispivotally supported with its marking end in engagement with a record sheet 26. The shaft 23c also supports parts cooperating with a bar 42 to effect adjustments of the pen support 28] which compensate for the expansion and contraction of the record sheet 26 caused by changes in atmospheric humidity. Such compensating provisions do not vary the position of the pen recorder carriage 23 though they vary the position of the pen or other marking element supported by said carriage, and form no part of the present invention and therefore need not be described herein.

The record sheet 26 passes over and is given feeding or advancing movements by a record feed roll 21. The latter is carried by a shaft Z' intermittently rotated by means, hereinafter described, actuated by the rocker 8 on each oscillation of the latter.

The control table A of the instrument show in Figs. 3 and 3A comprises a sheet metal frame having ear portions A apertured for the passage of a shaft B mounted 'in the instrument framework alongsidethe shaft 22 and havingibearing parts A which engage and slide along the upper flange of the rail 24 To facilitate the adjustment of the control table A along the path of travel of the pen carriage 23, the shaft B is shown as formed with a thread groove 3' receiving a cam or mutilated thread rib part A secured to the, control table frame. The shaft B may be rotated to adjust the control table in any suitable manner as by means of the transverse shaft geared to the shaft B and rotated by an operating handle or knob 13 at the front of the instrument, as shown in Fig. 1. An index A in conjunction with a scale on the front face of the rail 24 may indicate the adjustment of the table and the corresponding normal value of the quantity measured.

A member a is hinged at one edge to the frame of the control table A by a pivot or pintle shaft at extending parallel to the shaft B. The member a is formed with guiding provisions including a part o for a bar-like part C which extends parallel to the shaft B and is rigidly secured at its ends to arms C and C which are pivotally connected to the instrument framework so that the yoke-like structure formed by the bar C and arms C and C may turn with respect to the instrument framework about an axis C coinciding with that of the hinge connection a, between the table A and part a. The part a and bar C are held by the said guiding provisions against independent turning movements about the axis of their respective pivotal supports. The part a and bar C have a gravital tendency to move from their elevated positions, shown in dotted lines in Fig. 5, into or toward their lowermost positions. Their movement downward below their lastmentioned positions is prevented by the engagement of a projection C from the arm C with an adjacent portion of the instrument framework. The parts a and C are positively held in their uppermost positions by the action of a spring FA except during the portion of each revolution of the shaft [2 when the cam I l renders the spring FA inoperative to prevent such movement, as is hereinafter described. The extent to which the parts a and C are permitted to swing downwardly from their uppermost positions during each period when the action of the cam H renders the spring FA temporarily inoperative, depends upon the then relative positions of the table A and the recorder carriage 23, and upon other operating conditions later described. When the value of the quantity measured is so low that the carriage 23 is entirely at the low side (lefthand side, as seen in Fig. 3) of the control table A, the carriage 23 does not interfere with the movement of the parts a and C into their lowermost positions.

When the current value of the quantity measured is suitably close to the normal value of that quantity, the control table and marker carriage 23 are in such relative positions that downward movement of the hinged part a is prevented or restricted by the engagement of a portion of that part with the marker carriage 23. For purposes of such engagement the part a, as shown v in Figs. 3, 3A, and 8, has a carriage engaging portion a detachably secured to it. The part a is in the form of a plate with a downwardly projecting body portion terminating in a lower oblique edge a and having at its upper edge a lateral flange portion bearing against the under side of the part a at the rear edge of the latter and detachably secured thereto by clamping screws a". The bodies of said screws pass through slots in the part a which are open at the rear edge of the latter.

The lower edge a of the projection a is so disposed that it may engage and rest upon the shoulder 230 formed by the upper edge of the projection 23c at the high side of the recorder carriage 23 (the right hand side, as seen in Fig. 3), when the position of said carriage is such as to hold the shoulder 23C beneath said edge a.

When the indices 23d and A coincide, indicating that the predetermined normal condition of the quantity then exists, the midpoint of edge a will be directly over the right-hand edge of shoulder 230. As the carriage 23 deflects above and below its normal position, the point of contact of shoulder 23C and edge a varies so as to raise and lower bar C. The highest operative position of edge a corresponds to the position in which horizontal edge a of part a contacts shoulder 23C. The dotted position of Fig. 5 is an inoperative or clearance position in which part a cannot interfere in any way with the movements of the marker carriage which are given the latter while the part a is held in said clearance position. v

When an increase in the value of the quantity measured results. in a movement of the recorder carriage 23 to the high side of the control table A, that movement causes the part a to be positively secured against down movement from its uppermost operative position by adjusting latch member D, into its latching position. The latch D is pivotally mounted on a stud A depending from the underside of the plate-like body of the table A. In the latching position of the member D, a finger-like portion of the member extends beneath a portion a of the part a which is some distance to the rear of the hinge shaft a.

Latch member D is automatically moved into and out of its latching position, as the carriage 23 moves to and returns from the high side of the control table A, by means which include a vertically disposed shoulder or edge 23B of the projection 231) at the low side front corner of the recorder carriage frame, a member (1 pivotally mountedon a stud A depending from the under side of the control table frame alongside the stud A and a spring Dd connecting the members D and d. The spring Dd tends to move the member D in the counter-clockwise direction, as seen in Fig. 3A, and to move the member at in the opposite direction about their respective pivotal supports A and A such turning movements of the members D and d are prevented by the engagement of the finger portion at of the part (1 with the shoulder D of the member I), when the latter is in its latching position, as shown in Fig. 3A. In the non-latching position of the member D, the finger d engages a shoulder D of the part D.

The members D and d are moved from the latched position shown in Fig. 3A into the unlatched position and back again into the position shown in Fig. 3A by the engagement of the recorder carriage shoulder 233 with the camshaped front edges D and d of the members D and d, respectively. The edges D and d are so respectively shaped and disposed that as the carriage moves to the high side of the control table, the shoulder 23B acts on the edge d to turn the member d counterrclockwise, as seen in Fig. 3A, so that the spring Dd may then move the member D into its latching position in which its shoulders D engage the finger d. When the carriage subsequently moves back from its high position, the shoulder 23B engages edges D of the member D and moves thelatter into its nonlatching position while permitting the spring Dd to move the member d into the position in which its finger d engages the shoulder D of the member D, and holds the latter'in its non-latching position.

The means through which the spring FA normally prevents movement of the control table part u. out of its clearance position, and through which the rising and falling movements of the bar C and part a effect control functions, in-

clude a floating member E connected by a link C to the arm C and parts associated with the member E. The latter is pivotally connected at EF to. the part F of a compound lever comprising parts F and FA each pivoted to the instrument framework at F and normally held against relative movement by a spring FB. The latter tends to hold the part F in engagement with a projection FA of the part FA, but serves as a safety device which may yield to prevent injury of the parts in case the switch parts actuated by the member should jam; the spring FA extends between the upper end of the lever part FA and the instrument framework, and tends to hold the parts F, FA and E in the positions shown in dotted lines in Fig. 5.

The lever part FA is moved from the dotted line position into the full line position of Fig. 5 once during each rotation of the shaft I2, by the cam ll, which then engages a cam roll follower FA carried by the lever part FA.

When the parts are in the positions shown in dotted lines in Fig. 5, the lower cam edge E of the member rests upon a roller support e mounted on the instrument framework, and the position of the member E is then such that the link C holds the part C and thereby the bar C and control table part a in their uppermost positions. When the lever part F is turned in the clockwise direction from its Fig. 5 dotted line position, the weight of the part E adds to the gravital tendency of the bar C and table part a to turn downward, and the parts last mentioned then move downward into the position shown in full lines in Fig. 5, unless further movement is prevented by the control table latch D, or by the engagement of the edge a with the recorder carriage shoulder at 23C. 7

The movement of the member E into the full line position shown in Fig. 5 adjusts a control element H about its stationary supporting shaft I into a position, unless already in that position, which corresponds to and isdetermined by the then existing elevation of the member E which is determined by the position at the time of the part C The position of the member H following each advancing movement of the member E is made dependent on the elevation of the member E through the co-action of fingers G and G carried by the member E with lateral extensions H and H from an arm secured to the frame H and located at opposite sides of the shaft I. When the measured quantity is at its normal value, so that the shoulder 23C of the carriage 23 is in position to engage the midpoint of the oblique edge a of the control table A, the oppositely inclined engaging edges of the fingers G and G so engage the fingers H and H respectively, as to turn the member H into its central or normal position, shown in Fig. 7, if not already in that position. When the carriage 23 is deflected to the right or the left of -its normal value position as a result of the departure of the quantity measured above or below its normal value, the point of the control table edge d engaging the carriage shoulder 230 will so raise or lower the member E that the fingers G and G and projections H and H will insure a position of the member H displaced clockwise or counter-clockwise, respectively, from the normal position illustrated in Fig. '7. Any defiection of the carriage 23 thus produces a corre- .ing adjustment.

spending change in the angular position of the frame H.

The frame H carries a contactor h in sliding engagement with a resistor h shown as helically wound about a. support extending parallel to the chord of the arcuate movement of the contactor h occurring as the member H is oscillated about the shaft 1. One end of a conductor h is connected to the contactor h and through the latter is connected to the resistor h at a point along the length of the latter which depends upon the angular position of the frame H. The resistor h, contactor h, and conductor h constitute part of a control circuit, of which one form is shown in Fig. 2 and a different form is shown in Fig. 2A, which is adapted to effect adjustment in the rate of heat supplied to the burner U on a change in position of the contactor h resulting from a change in the glass temperature to which the thermo-couple I5 responds.

'The control circuit shown in Fig. 2 comprises two branch circuits connected in parallel with one another to a source of current through supply conductors hr and 71.1 The sidewire resistor h is included in one of said branch circuits and the conductor 71 connects the contact h to an intermediate portion hr" of the other branch circuit. Each of the two branch circuits thus forms two, arms of a bridge circuit energized by the conductors hr and hi and comprising arms hr, hl", m and hl The bridge arms hr and hl include relatively fixed resistances hr and hi respectively, which when once calibrated are not changed during the normal operation of the instrument. The arms hr and -hl' also include resistances hr and hi adapted for manual adjustment to vary the sensitivity of the control as hereinafter described. The resistor h includes a portion hr in the arm hr, and has its remaining portion hl included in the arm hl. The relative magnitudes of the portions hr and hl of the resistance 71. depends upon and varies with the adjustment of the contactor h effected by the angular adjustment of the frame H. The bridge arm hr includes the heating resistance he of the thermally actuated valve V of known type shown in Fig. 1, and the arm hl includes a resistor hl" which is adjustable by means of a sliding contact 711 When a decrease in the spout temperature to which the thermocouple l5 responds produces a deflection of the pen carriage 23 resulting in a movement of the contact h to the left as seen in Fig. 2, the resultant decrease in resistance of arm hl' relative to that of arm hrf, results in an increase in the current flow through the heating resistance he of the valve V, and gives an opening adjustment to the latter and thereby increases the fuel supply to the burner U Conversely an increase in the spout temperature and an adjustment of the contactor h to the right as seen in Fig. 2, and the resultant changes in the relative resistances of the arms hr and M will decrease the current flow through the heating resistance in: and subject the valve V to a clos- In the operation of the apparatus shown, insofar as it has been described, on the attainment of the predetermined normal spout temperature, the valve V will have a particular predetermined adjustment. Unless that adjustment is exactly the adjustment required for the supply by the burner U of the amount of heat needed for the maintenance of the predetermined normal temperature, the latter will not be main- Ill tained. In practice, the amount of heat which the burner U must furnish to maintain the predetermined normal temperature will vary from time to time. With the apparatus shown, the current flow through the resistance hi) and thereby the adjustment of the valve V, when the contact h is in its neutral normal temperature position, may be varied by adjustment of the contact hl Under certain conditions of use it is suflicient to provide means for effecting a. manual adjustment only of the contact hl Under other conditions, it is desirable to provide not only for the manual adjustment of the contact hl but an automatic compensating adjustment of the contact, whereby on an increase or decrease of the spout temperature from its normal value, a suitable adjustment of the contact hZ will be made to thereby decrease or increase the normal current flow through the resistance ho when the spout temperature is at its normal value.

The above mentioned compensating adjustment is effected with the form of apparatus shown, by

means of a contact member hC carried by the shaft I alongside the contact member h and engaging one or another or neither of two conductors TLC and n0 mounted on a support hC accordingly as the shaft I is deflected in one direc tion or the other from, or is in its neutral position. The engagement of the contact member hC with the conductor hC', occurring on a fall in the spout temperature above its normal value, results in the energization of a motor H0 in the direction required to adjust the contact hl to the right as seen in Fig. 2, and thereby increase the current flow through the resistance ho. To this end, as shown in Fig. 6, the motor HC includes a field winding HC' connected in series with the conductor hC' and the armature of the motor HC between motor energizing conductors H0 and HC. Conversely on a rise of the spout temperature above its normal value, the deflection of the contact member 710 into engagement with the conductor hC completes an energizing circuit between the conductors HC and HG including a second field winding HC in series with the conductor hC and motor armature and the motor HC is energized in the direction to decrease the current flow through the valve resistance ho.

As the compensating adjustment normally required is small, and in any event may advantageously be effected intermittently, the conductor HC, in the arrangement shown, is energized by means of a switch HC only when the latter connects the conductor HC to a conductor HC As shown, the switch HC is actuated once during each rotation of the constantly rotating instrument shaft i2 by means of a switch actuating cam HC carried by the shaft I2. With the arrangement shown diagrammatically in Fig. 6, the motor HC will be periodically energized .and produce corresponding adjustments of the contacts 711 during the smaller portions of time in which the instrument is not operative for its normal control purposes, as well as during the larger portions of time in which the instrument is so operative. The automatic adjustment of the contact hl during periods in which the instrument is not effecting its normal control functions is not seriously objectionable and ordinarily does not justify the slight additional instrument complication such as the inclusion of a secondswitch in series with the switch H6 and actuated, for example, by the means hereinafter described for operating the switch 39, so as to permit the motor HC to be energized only when the instrument is effecting its normal control functions.

As shown diagrammatically in Fig. 6, the armature shaft of the motor HC is connected to the shaft H0 carrying the contact hi through a friction clutch HC and the shaft H0 is gear connected to a knob hl mounted in the instrument panel, and by means of which the contact hZ may be manually adjusted at any time.

As an alternative to the adjustment of resistor hi through contacts hC, M3 and hC as just described to alter the normal current adjustment we may attain the same end of altering the normal fuel supply by direct mechanical actuation of valve V as shown in Fig. 1. In Fig. 1 we have indicated the motor H0 in dotted lines as connected to a throttling valve V governing the supply to valve V. The valve V may be and in practice is formed integral with valve V and is provided with a shaft V which we have shown as geared to reversible motor H0. The motor HC is energized as described in connection with Fig. 6. By this means the fuel flow to valve V is variably throttled and obviously a by-pass connection about valve V could be utilized to the same end.

In addition to the normal current adjustment just described and the normal temperature adjustment effected by operation of the knob 13 to adjust the control table A along the path of the marker carriage 23, it is highly desirable to adjust the control circuit so as to vary the sensitivity of the control effect, i. e. to vary the change in the fuel supply to the burner U resulting from a given change in the spout temperature to which the thermo-couple l5 responds. As shown in Fig. 2, the sensitivity adjustment is effected by simultaneously increasing or decreasing the amounts of the resistances hr and n1 included in the bridge arms hr and M respectively. To this end, as diagrammatically shown in Fig. 2, the contacts hr and 722 by which the amounts of the resistances m and M in circuit are respectively adjusted, are carried by rack bars HT and Hl The latter are at opposite sides of, and in mesh with a spur gear h which may be rotated as by means of a knob 11, mounted on the panel T. Rotation of the gear h in one direction will increase the amounts of the resistances hr and hl in circuit and thereby diminish the control sensitivity, and its rotation in the opposite direction will diminish the amounts of the resistances hr and M in circuit and increase the control sensitivity. The sensitivity adjustment thus provided, permits of a wide variation in the range of adjustment of the fuel 4 supply, and a consequent variation in the frequency of the swings in glass temperature resulting from changes in the glass spout temperature due to changes in the temperature at which the glass is supplied to the channel or other causes extraneous to the control system and to the compensating andv temperature restoring action of the burner U The advantage of the sensitivity adjustment provided for in the circuit arrangement of Fig. 2

winding Hr" is equal to, exceeds, or is less than .the cu re'nt'flow through the winding HP. The longitudinal movementof the armature H away from its neutral position moves a contact H pivoted at H into engagement with a contact Hr or a contact H1 dependent on the direction of armature movement, neither of the last mentioned contacts being engaged by the contact H when the armature H is in its neutral position. i v

The motor H is energized forrotation in one direction when the contact H engages the contact H1 through a circuit including supply conductor H contact H contact Hr conductor Hr", motor winding HM and supply conductor H Movement of the contact H into engagement with the contact Hi energizes the motor H, for rotation of its armature H" in the opposite direction through an energizing circuit similar to that just described except that it includes motor winding H1 conductor HZ" and contact H in lieu of the motor winding HT", conductor H and contact H The rotation of the motor H in one directio 'or the other gives a corresponding angular adposition of the contactor It. What that corre-- thus corresponds to the position of the movable member of the valve V. The contactor H is connected by a conductor H to the common junction of the windings Hr and HF, and engages, and isadjustable along a slidewire resistance H, which is connected in shunt to the bridge circuit branch including the arms H1 and H In the normal position of the contactor h corresponding to the normal value of the spout temperature, the floating armature H the contactor H and the movable member of the valve V will all be in, or move into, their normal midpositions. A change in the spout temperature resulting in an adjustment of the contactor h will unbalance the current fiows in the windings H1 and H and thereby set the motor H in operation to effect the same kind of adjustment .in the fuel supply to the burner U as would result from the same adjustment of the contactor h. with the circuit arrangement of Fig. 2 provided that the sensitivity adjustment is the same in Fig. A as in Fig, 2. The arrangement of Fig. 2A differs from that in Fig.2, however, in that the movement of the motor 1-! which adjusts the valve 'V' also, adjusts thecontact H7.

operation of the motor H tends to rebalance the current flow in the windings H1 and HZ and continues until rebalance is adjusted. In

consequence, on any changein the control temperature and consequent change in the position ofthe contactor h, the motor H operates until the position of the movable valve member of the valve V and the position of the contactor H" are in predetermined correspondence with the spondence may be dependsupon the sensitivity adjustment of the circuit and is varied by a variation in that adjustment.

The above mentioned application. Ser. No.

The ad-' justment of the contact H resulting from the vvisions for intermittently printing independent records of various quantities. For the purpose of the present invention we advantageously employ so-called pen dragging" means forming a continuous record line as shown in Fig. 11, different readily distinguishable portions of which show the spout and channel temperatures. Advantageously, and as shown, the time cycle of operation of our recorder controller instrument is divided into three stages which are respectively represented in Fig. 11 by consecutive curve portions Nib-2 60, 26c--26d, and 2611-2612.

During the period or stage in which each curve section 2Gb 23c is being traced, the channel thermocouple I5 is connected to the potentiometer measuring circuit and that period is terminated as soon as the instrument attains a predetermined condition or status hereinafter explained, which is assumed to and normally does insure a true measurement of the thermocouple voltage. At the termination of each of the periods or stages just referred to the switch 39 is actuated, as hereinafter explained, to disconnect the thermocouple l5" from and to connect the thermocouple l5 into the measuring circuit. That condition or status is normally attained when a predetermined plurality of consecutive rebalancing operations occur without requiring adjustment of the pen carriage 23 and contactor 20. With the considerable difference between the temperatures indicated on the chartby the lateral displacement of points 26b from the points 260, a number of instrument rebalancing operations will occur as the pen is moving to the left, as seen in Fig. 11, from any point 26b to the following point 260, but the adjustment of the pen carriage and contactor 20 effected at each rebalancing operation will be insuificient to fully balance the potentiometer circuit. After the pen point reaches the point 260, which represents a true measure of the channel temperature, a small number of subsequent consecutive rebalancing operations can ordinarily occur without producing any adjustment of the car .riage 23 and contactor 20, under the normal condition in which the channel temperature changes so slowly that time required for a large number'of consecutive rebalancing operations may elapse before the .channel temperature changes enough to require a change in measuring adjustment of the contactor 20 and carriage 23. The different points 26c thus collectively constitute a sufiicient record of the channel temperature during the time in which those record points are formed.

The spout temperature measuring thermocouple I5 is connected to the potentiometer measuring circuit during each period or stage in which a curve section 26c26d is being formed, and the' latter is formed by instrument operations similar to those which result in the formation of a curve section 26b-26c.

With the particular form of mechanism disclosed, the shaft 34 is advanced a twelfth of a turn at the end of each stage during which a curve section 260-2611 is formed and thereby initiates the third stage represented by the corresponding curve section 26d 26b. As herein- .after explained, however, the character of the of the last mentioned period or stage. The latter would be completed sooner than is desirable but for means, hereinafter described, for rendering the means for rotating the shaft 34 inoperative during a predetermined time interval following the initiation of each stage in which a curve section 26L 26b is formed. During ,each stage represented by a curve section 2611-262), control effects are produced dependent upon the spout temperature measurements then being recorded.

, But for provisions now to be described, the instrument would produce undesired control effects during the periods in which the curve sections ZED-26c and 26c26d are being formed. While the channel thermocouple I5 is connected into the measuring circuit, control effects are not wanted, of course, since the control provided is responsive to the spout temperature only control actions while a curve section Zlic-ZGd is being formed are undesirable because, as already explained, the instrument does not give a true measurement of the spout temperature until the section is practically completed.

For the particular use of the invention described it is desirable that the instrument should measure and record the spout temperature and produce control effects in accordance therewith throughout as large a portion of the time as is consistent with suitably frequent measurements of the channel temperature, and, as indicated in the chart, the fixed time interval corresponding to the distance longitudinally of the chart between each point 26d and the following point 26b is appreciably greater than that represented by the corresponding distance between each point 26b andthe following point 26d. The last mentioned distance may vary somewhat since it cor- I responds, as will be apparent from what has been said, to the time required for a variable number of rebalancing operations.

The switch 39 which connects the thermocouple l5 and I5 alternately into the measuring circuit, is shown in Figs. 8 and 9 as mounted on the instrument side plate at the left hand side of the instrument as it appears in Fig. 3. The switch 39 may be of the type disclosed in the Harrison patent, 1,770,918, granted July 22, 1930, and is actuated by the rotation of a shaft 34, which in the form shown is given intermittent angular movements in the direction indicated by the arrow in Fig. 8, and each of 30. Twelve intermittent movements are thus required for a complete revolution of the shaft 34, and during each revolution of the shaft 34, therefore, the instrument completes its above mentioned threestage cycle of operation four times. For the three-stage cycle operation described herein it would be possible to arrange for a complete revolution of shaft 34 in three steps instead of l2, but with the l2 steps the instrument has a desirable flexibility or adaptability for other uses. The switch contacts are carried by a. shaft to which is fixed a gear 39a in mesh with and driven by a gear 34a carried by a shaft 34, the gear ratio being such that the switch shaft makes two revolutions for each revolution of the shaft 34. As will be apparent for the three-stage cycle operation described, the switch contacts must be so arranged that the thermocouple 15" will be connected into the measuring circuit while the gear 390 makes a sixth of a revolution and so that the thermocouple l5 will be connected into the measuring circuit duringthe subsequent movement of the gear 39a through a third of a revolution, after which the thermocouple i5 is again connected in the circuit while the gear 39a makes another sixth of a turn, etc. The periods during which the thermocouple l5" and I5 are in circuit are indicated by the movement of a pointer 39c along the arcs Ch and SP of the dial 38 shown in Fig. 10. The pointer 39a is carried by a shaft 390 on which is fixed a gear 391) in mesh with the upper end portion of the gear 39a, the gear ratio of gears 39a and 39b being l-to 1.

The shaft 390, which carries the pointer 3913 at one end, carries at its end a control holdout device 39d comprising disc parts 39d and 39d" which serve to hold the control instrumentalities out of operation except during the periods or stages in which curve sections 26d-26,b are being formed and in which the pointer 39c is moving through along the second half of each dial arc SP. The disc parts 39d and 390'." are provided with peripheral notches so related that the composite disc formed by the two parts 39d and 39d" when clamped together by the clamping screw 39d, will have one or more peripheral notches depending on the relative angular positions of the parts 39d and 39d". For the particular instrument use illustrated herein, the two disc parts are relatively disposed to provide two diametrically opposed peripheral notches 39 and 39f as is shown clearly in Fig. 9. During each control stage in which the pointer 396 is moving through the last half of each arc SP of the dial shown in Fig. 10, a lever C turning loosely on the shaft 34 may dip into one or the other of the notches 39 and 39f While during the other stages similar down movements of the lever C are prevented by the engagement of the latter with unnotched portions of the composite disc periphery. The

lever C is connected by a link C and pivot pin C to the previously mentioned arm C which moves up and down with the control bar C. During the stages in which the curve sections 261}- 26c--26d are being formed, the bar C is prevented from moving downward from a position which corresponds substantially to, but is slightly below its dotted line position shown in Fig. 5 by the engagement of the lever C with an unnotched peripheral portion of the device 39d. The elevated position in which the bar C and arm C are then held, makes the elevation of the device E such that when the latter is advanced its fingers G and G2 pass above the control frame projections H and H respectively, and in consequence cannot then subject the frame H and contactor h to a control action.

An alternative means for elevating to and holding bar C in the raised position just described is shown in Fig. 8A. In Fig. 8A a cam 39D secured to shaft 34 is adapted to rotate with the latter and positively raise a link CA corresponding to link C of Fig. 8 thereby raising arm C to which it is pivoted at C The link CA is bifurcated at its lower end and surrounds a bushing secured to shaft 34 which bushing serves as a guide for the vertical motion of the link. A roller CA carried by lever CA is adapted to ride on the edge of cam 39D in the latter of which is provided the depressions 39F, 39F, 39F and 391* corresponding in purpose to depressions 39f and 39] of Fig. 9.v The lever CA is free to drop four times in each revolution of shaft 34 if the relation of table a and carriage 23 is such as to permit downward motion, the four stages in which roller CA is opposite a depression in cam 39D corresponding to the controlling stage in which pointer 39c is at the latter portion of the area indicated as 2 in Fig. 10.

v 2,168,92Q The mechanism through which the shaft 34 is given its successive 30 turning movements required,for the production of the curve shown in Fig. 11, is illustrated in Figs. 4 and 4A, which are elevations of the instrument as seen from the side of the latter opposite to that shown in Fig. 8. At the side of the instrument shown in Figs. 4 and 4A, a ratchet wheel 36 is secured to the shaft 34, a keeper 36' preventing counter-clock The pawl 31 is pivoted at 3?", to a'pawl lever 38, the latter being freely pivoted on shaft 34.

A spring 43 tends to hold the pawl 31 against the periphery of the wheel 36 and normally holds the ratchet lever 38 in its uppermost position in which it bears against a fixed stop 44'.

The ratchet lever 38 is turned clockwise from the position shown in Fig. 4 about the shaft 34 to advance the wheel 36 one tooth (i. e., one-twelfth of a revolution) on each oscillatory movement of the previously mentioned rocker 6 in the counter clockwise direction occurring at a time in which a lever 46 holds a thrust member 45 in the full line position shown in Fig. 4 in which said member bears against a stop 44'. In that position, the member 45, which is pivoted on the pivot pin 31, acts as a thrust block interposed between the pivot .pin 31' and the projection 6 at the end of the arm 8' of the rocker 8. The turning move-. ment about the shaft 34 then given the lever 36 as theprojection 8" descends, carries the arm 38" of lever 36 into the position 38A shown in dotted lines in Fig. 4, and in turning into its dotted line position, the arm 36" engages the lower end 46" of the lever 46 and the lower end 48" of another lever 43 and turns those levers into the positions indicated by the dotted line positions of their lower ends shown in Fig. 4. As

the rocker arm 8' makes its return upstroke, the

spring 43 returns the lever 36 to its full line position, but does not effect a corresponding return movement of the lever 46. In consequence, the member 45 then is gravity held on its dotted line position shown in Fig. 4, in which it rests against .pin 31" carried by the lever 38, and in which its upper end'is out of the path of movement of the projection 8". No subsequent counter-clockwise rotation of the rocker 8 gives movement to the lever 38 and ratchet wheel '36 until the lever 46 is again returned to its full line position.

The lever 46 is returned to its full line position as a result of a plurality of rebalancing operations, said plurality varying from a minimum of two up to a predetermined but adjustable maximum which may well be from 6 to 20 or thereabouts, and which is fixed by means hereafter described. The levers 46 and 48 are mounted to turn about the supporting stud 9 for the rocker 8, and are so mounted as to have a. frictional tendency to remain in the positions assumed by them until subjected to external forces displacing them from such positions. The lever 46 is returned to its full line position by the direct, indirect or partly direct and partly indirect action of a pawl 41 pivoted at 41 to an arm of the rocker 8. The direct action on the lever 46 of the pawl 41 cccurs when the pawl engages with one or'first with 4 one and then with another of two teeth 46' carried by the upper end of the lever 46. The indirect action of the pawl 41 on the lever 46 results from the engagement by the pawl of the teeth 48' carried at the upper end of the lever 48 and the movement of the lower end of the latter against a projection 46a adjustably'secured to the lever 46. Movement of the lever 48 under the action of the pawl 41 occurring after the lever has engaged the projection 46a, moves the lever 46 toward and may eventually move it into its full line position. The means for varying the number of teeth 48' by which it is necessary to move lever 46 before the lower end of lever 48 engages projection 46a, includes a notched sector 46b which carries projection 46a and which is pivoted at ii. One or another of notches 460 of sector 4622, according to the adjustment desired may be engaged by a projection 46d of lever 46 to thereby rigidlyconnect the projection 46a to the lever 46. In the adjustment shown in Fig. 4, twenty actuations of teeth 46 are required to move the block 45 into position for engagement by rocker arm 6' while but six such actuations would be required if the relative adjustment of lever 46 and sector 461) were such that uppermost tooth 46c engages projection 46d.

Whether or not on any particular clockwise rotation of the rocker 6 the pawl 41 will engage a tooth 46 of the lever 46 depends upon the po sition at the time of a tooth shielding member 49. The position of the member 49 at that time depends indirectly upon the position of the secondary pointer l4 and depends directly upon the position of the drive lever i6 when its advancing movement is arrested by the engagement of one of the shoulders of part i6G with the secondary pointer projection 14''. The position of the member 49 is so controlled as a result of the fact that it tends to turn clockwise under the action of gravity about the stud 9 to which it is pivotally connected and that its gravital movement is controlled by the engagement of a cam edge portion ofthe member 49 with an extension of the pivot pin I6D' on which the follower roll i6D is journalled.

In the neutral position of the secondary pointer i4" and a perfect or approximately perfect condition of potentiometer balance in which the shoulder I6G" engages the projection I4", the part 49 is held in its uppermost position by the pin. I6D. The pawl 41 is then free to engage a tooth 48' and a tooth 46' at the beginning of its down stroke and to maintain such engagement until said stroke is completed. If in such case at the beginning of said stroke the lever 46 is in its position most remote from that shown in full lines in Fig. 4, the pawl 41 will then engage the lower tooth 46' and move the lever 46 into an intermediate position in which the pawl 41, on its following down stroke, can engage the second tooth 46', if the member 49 is then also in its uppermost position shown in Fig. 4. In such case the return of the, member 46 to its full line position is effected by two potentiometer rebalancing operations and results from the direct action of the pawl 41 on the teeth 46'. While in such case the pawl 41 on each stroke would engage a tooth 48' of the lever 46 and give the latter the same turning movement as is given to the lever 46, the movement given to the lever 48 would not contribute to the return of the lever 46 to its full line position. From theforegoing, it will be apparent that. in normal operation each actuation of the toothed wheel 36, effected through the parts 31 and 45 and the mechanism acting on the latter, institutes a new measuring period and terminates the measuring period which began with the previous actuation of the wheel 36 by the pawl 31, part 45 and mechanism acting on the latter. It will be noted further that each measuring period ends either when the measuring apparatus attains a predetermined measuring status, which, with the particular form of embodiment illustrated herein, is that resulting in perfect balance at two balancing operations during the measuring period, or at the end of a predetermined number of balancing operations when said status is not obtained with a smaller number of balancing operations.

When at the beginning of the down stroke of the pawl 41, the projection l4 engages one of the upper or lower shoulders 166 so that the pivot pin IGD then occupies a position downward and to the left of that shown in Fig. 4, the member 49 will occupy a lower position in which it prevents the pawl 41 from engaging either tooth 46' or from engaging any tooth 48' until the down stroke of the pawl 41 is so nearly completed that it will advance the tooth 48' engaged, only for a distance corresponding to the distance between that tooth and an adjacent tooth 48. If the series of rebalancing operations preceding each partial rotation of the ratchet wheel 36 includes none in which perfect balance is attained, the lever 48 will be advanced a tooth at a time until the predetermined number of such advances has caused the lever 48 to engage the projection 46a and move the lever 46 into its full line position. Whenever in that series of operations perfect balance is obtained, the next downstroke of the pawl 41' will directly move the lever 46 either into it said intermediate position or into its full line position and will correspondingly advance the lever 48. It will be apparent, therefore, that the lever 46 may be moved from its initial position into its full line position by the first'two balancing operations of each if each of those operations results in perfect balance, or by any greater number of rebalancing operations including either one or two in which perfect balance is obtained up to a maximum number of rebalancing operations required for the return of the lever 46 by the advancement of the lever 48 one step at a time, in case perfect balance is not attained prior to the last downv stroke of the pawl 41 required to return the lever 46 through the action of the lever 46. 4

The adjustment of the member 45 into the position shown in Fig. 4 during the stage in which the channel temperature is being measured results in the actuation of the shaft 34 which terminates that stage and initiates the second stage in which the potentiometer is balanced to measure the spout temperature. The movement of the member 45 into the Fig. 4 position during the last mentioned stage results in a movement of the shaft 34 which terminates thatstage and initiates the third stage. The last mentioned movement of the shaft 3t, while actually adjusting the switch 39, does not cut the thermocouple l5 out of and the thermocouple l5" into the measuring circuit because of the switch characteristics already mentioned, but does advance the disc parts 39d and 39d to bring one or the other of the notches 39 and 39)" into position beneath the lever C so that the instrument may then perform its control functions effected during each third stage.

When the member 45 is brought into its Fig. 4 position during each third stage operation, it does not result immediately in a corresponding partial rotation of the shaft 34 because of the means previously mentioned and now to be described for rendering the provisions for rotating the shaft 34 inoperative for a predetermined time interval. The means last referred to comprise a masking member Y pivoted at Y, which when in its position shown in Fig. 4 is idle, but when in its position shown in Fig. 4A, has its cam edge Y in engagement with a roller 31a on the pawl 31 and holds the latter away from the ratchet wheel 36. While the pawl 31 is so held away from the ratchet wheel 36, downstrokes of the member 45 and pawl 31 then produced are idle strokes and give no movement to the shaft 34. The masking member Y is moved from its position shown in Fig. 4 to its position shown in Fig. 4A at the beginning of each stage in which control actions are effected in accordance with spout temperature measurements by the engagement of the member Y by a corresponding one of four pins 34b carried by a disc 34a secured to the shaft 34, the pins being equally spaced about the axis of the shaft.

The previously mentioned spring 43, which is connected at its lower end to the pawl 31, is connected at its upper end to the member Y and subjects the latter to a yielding force constantly tending to turn the member Y about the pivot pin Y in the clockwise direction as seen in Fig. 4. The spring 43 is advantageously connected to the member Y through a member Y which is pivotally mounted on the pin Y carried by the member Y. Except under conditions hereafter referred to, the spring 43 holds the member Y against the stop pin Y and acts on the member Y as though connected to a rigid portion of the latter.

In the preferred construction shown, the in strument includes means normally operating to return the member Y to its Fig. 4 position at the end of a predetermined time interval following each movement of the member out of that position, said means comprising a cam member Z which is in effect a ratchet wheel. The cam Z is secured to the chart drive shaft Z The shaft Z is rotated slowly and at an approximately constant speed in the counter-clockwise direction as seen in Fig. 4, and may be so rotated by any usual or suitable chart advancing mechanism. In the particular instrument shown, the shaft Z is rotated by a shaft Z (Fig. 5) carrying a worm Z (Fig. 3) which drives a worm wheel Z mounted on the shaft Z and preferably connected to the latter through a friction drive part Z so that while the shaft Z normally rotates with the gear Z it may be manually adjusted angularly relative to the latter, as is cocasionally desirable in effecting the proper time setting of the record chart and for other purposes. In the form of construction shown, the shaft Z is intermittently advanced by a pawl and latch mechanism actuated by the arm 8 of the rocker 8, but that mechanism need not be described in detail herein as it forms no part of the present invention and is described in the above mentioned application, Serial No. 546,290, and in the above mentioned Patent No. 1,946,280. While the motion given by the mechanism to the shaft Z is intermittent, the periodicity or frequency of its intermittent movements is so great, relative to the slow record chart movement. that 'the latter from its Fig. 4A position to its Fig. 4

position, by virtue of the fact that the movement of the member Y into its Fig. 4A position swings a shoulder Y carried by the member Y into position for entrance between two teeth Z of the cam Z, so that as the latter rotates, the rear tooth may engage the shoulder Y and lift the member Y. The lifting movement of the latter normally continues until its surface previously engaged by a pin 3412 as shown in Fig. 4A, is lifted above that pin. The tension of the spring 43 then turns the member Y into its Fig. 4 position which carries the shoulder Y out of the path of the cam teeth Z Advantageously, and as shown, the shoulder Y is carried by the pivoted part Y which can turn counter-clockwise about its pivot Y against the tension of the spring 43 and thereby prevent the parts from jamming under certain conditions, as when it becomes desirable to give a manual reverse rotation to the chart shaft Z while the shoulder Y is entered between adjacent teeth Z of the cam Z. In such case the counter-clockwise movement of any tooth Z engaging the shoulder Y will cam the latter out of the path of the. tooth. The arrangement also prevents jamming in case the movement of the member Y into itsFlg. 4A position occurs at such a stage in the rotation of the cam Z that the shoulder Y engages the tip of a tooth Z In such case, the lifting movement of the member Y does not begin until the end of the short period required for sufflcient movement of the cam Z to permit the shoulder Y to enter the space back of the tooth Z initially engaged.

As shown, the member Y is formed with an opening Y through which the shaft Z passes and which is sufficiently large to provide clearance for the described movements of the member Y relative to the shaft Z The return'of the member Y to its Fig. 4 position renders the part 45 operative on its next downstroke to advance shaft 34, thereby terminating the third stage of the operating cycle and initiating the first stage of the following operating cycle. The return of the member Y to its Fig. 4 position leaves the pin Y in an intermediate portion of the length of the slot Y as the member Y is then held above its lowermost position by the pin 341) which had turned the member Y into its Fig. 4Aposition. As the shaft 34 is angularly advanced thereafter, the movement of the pin last mentioned permits the member Y to descend into position'for engagement by the following pin 34!), when the member Y- is next to be advanced into its Fig. 4A position.

In the-operation of the apparatus of Fig. 1 with control mechanism associated therewith as hereinbefore described, the supply of fuel of the spout burner U is automatically controlled in accordance with the temperature of the molten glass about to be extruded. The type of control produced by us, namely, a stabilized followup control, is practicallyeffective for its intended purpose of keeping the temperature of the glass in the spout suitably close to a desirable normal value of that temperature while avoiding rapid changes in that temperature. As previously explained, the effective length of stroke of the glass extruding plunger U may be varied as required to main the desirably constant glass gob weight. To this end, as diagrammatically shown in Fig. 1, we may provide gob weighing means in the form of a balance pivoted at U and comprising a gob receiving platform U beneath the plunger U and gob severing clipper means. When a glass gob is received on the platform U of the balance, the weight of the gob is indicated on the scale U and when the gobweight exceeds or falls below a predetermined value, the screw U may be adjusted to shorten or lengthen, respectively, the stroke of the plunger U.

As shown in Fig. 1, the screw U is manually adjusted, but means may be provided for automatically adjusting it as required to correct for variations in the weight ofthe gobs discharged from the desired or normal weight. One arrangement for so automatically adjusting the plunger stroke is diagrammatically illustrated in Fig. 2B. weight, it is in general immaterial whether the gob itself, or the bottle or other article produced from the gob is weighed as is provided for in Fig. 2B, except that it is not practically advantageous to weigh the gob prior to its conversion into the-article formed. In Fig. 2B, UA represents a travelling conveyor receiving the gobs as they are formed and transmitting them into the article forming apparatus U18. The articles formed in that apparatus are moved away from the latter by a travelling conveyor UC which has its article carrying run passing over and supported by the platform UD' of ,a weighing scale U1). The weighing device U'D includes a pointer UB which is deflected into a position adjacent one or the other of two motor control contacts In automatically controlling the gob stantly running motor UE and thereby moved into engagement with one or the other of the two contacts, if the pointer is then deflected to the one or the other side of its normal weight position between the two contacts.

The engagement of the pointer UD" with the contact UE closes one of the two energizing circuits for a reversible motor UG which is thereby operated to rotate the screw U" in the direction to shorten the stroke of the plunger U and decrease the weight of the gobs extruded. When the pointer UD engages the contact UE the second energizing circuit for the motor UG is closed and the motor then operates to adjust the screw U" in the direction to lengthen the stroke of the plunger U and thereby increase the weight of the gobs discharged. As diagrammatically shown, the motorUG rotates the screw U" by virtue of the fact that a gear UG rotated by the motor is in mesh with a gear U" carried by the screw U",

'one of the two gears being sufflciently elongated to preserve their operative relation, notwithstanding axial movement of the screw U". Preferably, the periodicity or frequency of operation of the depressor UN is sufllciently low relative to that of the plunger U, so that the effect of each operation of the motor UG and corresponding adjustment of the plunger U may manifest itself in the weight of the article above the platform UD before a subsequent operation of the motor can occur, or a well known follow up device may be employed to affect a movement of contacts U'E-JJE or pointer UD in response to actuation of motor UG.

As will be apparent to those skilled in the art, 

